An internal combustion engine may operate in a variety of different modes, particularly in modern engine systems, which are electronically controlled, based upon a variety of monitored engine operating parameters. Some typical operating modes include a cold mode, a warm mode, a cranking mode, a low idle mode, a high idle mode, and an in-between mode which is between the low idle mode and the high idle mode. Various engine operating parameters may be monitored to determine the engine operating mode including engine speed, throttle position, vehicle speed, coolant temperature, and oil temperature, as well as others. In each operating mode it is not uncommon to use different techniques to determine the amount of fuel to deliver to the engine for a fuel delivery cycle. For example, different fuel rate maps might be utilized in two different modes or a fuel rate map might be used in one mode and in another mode an engine speed governor with closed loop control may be used. One of these maps is a torque map which uses the actual engine speed signal to produce the maximum allowable fuel quantity signal based on the horsepower and torque characteristics of the engine. Another map is the emissions, or smoke limiter map, which limits the amount of smoke produced by the engine as a function of air manifold pressure or boost pressure, ambient temperature and pressure, and engine speed. The maximum allowable fuel quantity signal produced by the smoke map limits the quantity of fuel based on the quantity of air available to prevent excess smoke.
Known hydraulically-actuated fuel injector systems that use smoke maps and torque maps are shown, for example, in U.S. Pat. No. 5,586,538. Such systems utilize an electronic control module that regulates the quantity of fuel that the fuel injector dispenses. The electronic control modules include software in the form of maps or multi-dimensional data tables that are used to define optimum fuel system operational parameters to regulate the quantity of fuel that the fuel injector dispenses, such as the torque map and smoke map discussed hereinabove. However, such lookup tables are typically developed in response to a predetermined engine temperature. Consequently, when the engine temperature deviates from the predetermined engine temperature, the actuating fluid viscosity changes which causes the fuel injectors to dispense a greater or lesser amount of fuel than that desired. For example, a torque map designed for use once the engine has reached warm operating temperatures will not deliver enough fuel to generate the desired power in cold operating conditions.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.